Ophthalmic surgical instrument with pre-set tip-to-shell orientation

ABSTRACT

An ophthalmic surgical instrument comprises a multi-diameter shaft, a horn fixedly threaded into the shaft, a surgical tip for ophthalmic surgery including a tip end and threadably engaging the horn opposite the shaft, and a plug on the shaft. Weld material holds the plug on the shaft in a selected angular and longitudinal position with an angle-locating recess on the plug&#39;s circumference having a predetermined angular clocked relation to a face direction of the tip end. The plug&#39;s recess engages an irrigation tube on a subassembled handle with shell and irrigation tube, such that the subassembled handle has a known clocked position relative to the tip end of the tip, thus facilitating use by a surgeon. A related method is also disclosed and claimed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/757,983, filed on Feb. 4, 2013, entitled OPHTHALMIC SURGICALINSTURMENT WITH PRE-SET TIP-TO-SHELL ORIENTATION which claims benefitunder 35 USC §119(e) of provisional application Ser. No. 61/709,540,filed Oct. 4, 2012, entitled OPHTHALMIC SURGICAL INSTRUMENT WITH WELDEDIRRIGATION TUBE; provisional application Ser. No. 61/709,547, filed Oct.4, 2012, entitled OPHTHALMIC SURGICAL INSTRUMENT WITH ONE-PIECE SHELL;and provisional application Ser. No. 61/709,568, filed Oct. 4, 2012,entitled OPHTHALMIC SURGICAL INSTRUMENT WITH PRE-SET TIP-TO-SHELLORIENTATION, the entire contents of each of which are incorporatedherein by reference.

BACKGROUND

The present invention relates to an ophthalmic surgical instrument withcomponents facilitating clocked orientation of a surgical tip to itsouter shell/handle, and components facilitating dimensionally-accuratemanufacture including defect-free welding.

Ophthalmic surgical instruments are highly refined medical tools used ineye surgery, such as for cataract lens extraction. Such products arecommercially manufactured and available, such as from Alcon company,including for example the Infinity® Vision System and/or Ozil® VisionSystem. It is important that the surgical instrument that contacts thepatient and that is handled by the surgeon be of the highest quality,since the human eye is a delicate organ and the surgical procedure isvery delicate. Therefore, reliability, durability, safety, ease of use,ease of sterilization, and numerous other aspects of the surgicalinstrument and related methods are very important. Also, physiciansdemand high quality and appealing aesthetics. At the same time, cost andmanufacturability is important.

One tip used with hand-held ophthalmic surgical instruments is areplaceable tip, such as a phaco tip, with a straight end with beveledtip end, or a slightly bent/curved end with oriented tip end. Surgeonsprefer that the bent/beveled end have a particular orientation relativeto the handle when the surgeon picks up the instrument, so that thesurgeon does not have to look to see the orientation of the bent/beveledend. In other words, surgeons want to intuitively known which way thebent/beveled end is “facing” when they pick up the instrument based onfeel. The relative rotational orientation of parts is referred to hereinas “clocking”. Threaded connections provide an inconsistent angularrotational position (i.e. inconsistent “clocking”), particularly whentorqued to a desired preload. Preloading is a requirement for thesetips, since the instruments sonically vibrate the tips during use, and asignificant torsional preload is required to prevent unacceptable riskof loosening during use. Depending on the design, the instrument mayhave multiple threaded connections for supporting the tip (e.g. a tipthreaded into a horn, and also the horn threaded into a support shaftand/or to the handle/shell). Multiple threaded connections furtheramplify the problem of inconsistent “clocking” of the bent/beveled endto the instrument's handle/shell. Specifically, the combination of thethreads, the preloads, and tolerance stack-up of the multiple componentsof the instruments makes it difficult to predict exactly what directiona bent/beveled end may face in a fully assembled instrument, thusresulting in an unacceptable number of bent/beveled tip ends beingoriented outside a preferred angular range.

Some existing manufacturing processes and instrument designs attempt todeal with this clocking problem by replacing one or more of the threadedconnection(s) with a press-fit arrangement, where the final clockedrotational position of the bent/beveled end (and/or of interconnectedcomponents affecting clocking of the bent/beveled end) is set by apress-fit process. However, press-fit assembly processes do not providea strength, robustness, and durability of threaded connections. Further,the tips must be replaceable, which press-fit does not support. Stillfurther, standard existing tips include threaded connections, so it isdifficult to eliminate the use of threads, since the industry presentlyuses them. Nonetheless, it is potentially a significant advantage toprovide features and/or characteristics that result in componentspre-set at the factory to have a particular clocked orientation whenassembled, such as at a supplier's site, rather than requiring this bedone at the overall system equipment manufacturer/assembler.

The handset in the present ophthalmic surgical instrument includesseveral components made of titanium that are fixedly connected bywelding. Though titanium is a preferred material for the presenthandset, titanium is difficult to weld in a defect-free manner. At thesame time, surgical handsets must be made defect-free so as to avoid anycracks, crevices, or imperfections that might harbor germs and unwantedorganics and contaminants. Notably, defects in handsets can cause anincrease in sterilization time and/or frustrate optimal sterilization.Also, defective handsets can have appearance issues causing surgeons toobject to or misinterpret the handset's quality.

In addition to high standards for defect-free handsets, ophthalmichandsets also have high standards for dimensional consistency andaccuracy. Further, the handsets must be light in weight to facilitateeasy and non-tiring use by the surgeon. Also, it is preferable that thehandsets use a minimum of materials to reduce manufacturing cost. Thisleads to a dilemma where the handset's outer shell must preferably bethin-walled, yet thin walls can cause secondary problems. For example,some instrument designs require a thin-walled outer shell (such as anextruded thin-walled outer shell) welded to a machined tip. However, itis difficult to weld onto thin walls without distortion (due to the heatrequired for good welding, and/or issues related to non-uniform heatingand later cooling), thus leading to welding defects and/or dimensionaldefects, especially near the weld area.

Thus, improvements are desired that positively affect each, any and allof the above items.

SUMMARY OF THE PRESENT INVENTION

In one aspect of the present invention, an internal subassembly for anophthalmic surgical instrument comprises a multi-diameter shaft, a hornfixedly threaded into the shaft and that is constructed to provide sonicvibration energy to an end opposite the shaft, a surgical tip forophthalmic surgery including a tip end at one end and a threaded endthreadably engaging the horn opposite the shaft, the tip end defining aface direction, a plug on the shaft, and a flange with an angle-locatingfeature. The subassembly further includes weld material holding the plugon the shaft in a selected angular and longitudinal position with theangle-locating feature having a predetermined angular clocked relationto the face direction of the tip end.

In a narrower form, the angle-locating feature is a recess in an annularflange on the plug.

In another aspect of the present invention, an ophthalmic surgicalinstrument is provided that includes a second outer subassemblyincluding a tubular shell and an irrigation tube attached to a side ofthe shell. The instrument includes the internal subassembly, asdescribed above, assembled into the second outer subassembly with therecess engaging the irrigation tube on the annular flange of the plug,thus causing the tip end to be in a desired angular clocked positionrelative to the irrigation tube on the shell.

In another aspect of the present invention, a method of manufacturing aninternal subassembly for an ophthalmic surgical instrument comprisesproviding a multi-diameter shaft, providing a horn adapted to generatesonic vibration energy, fixedly threading the horn and the shafttogether, providing a surgical tip for ophthalmic surgery including atip end at one end and a threaded end, threadably engaging the tip intothe horn opposite the shaft, the tip end defining a face direction,providing a plug on the shaft and a flange with an angle-locatingfeature, and welding the plug to the shaft in a selected angular andlongitudinal position with the angle-locating feature having apredetermined angular clocked relation to the face direction of the tipend.

In a narrower form, the angle-locating feature is a recess in an annularflange on the plug, and wherein the step of welding the plug includesengaging the recess with a feature in a welding holding fixture.

In a narrower form, the method includes providing a second outersubassembly having a tubular shell and an irrigation tube attached to aside of the shell, and including assembling the internal subassemblyabove into the second outer subassembly with the recess engaging theirrigation tube on the annular flange of the plug, thus causing the tipend to be in a desired angular clocked position relative to theirrigation tube on the shell.

In one aspect of the present invention, an ophthalmic surgicalinstrument comprises a combination including a tubular shell having atip end portion and a tail end portion, and further having a channelextending from a hole into the tubular shell near the tip end portionand extending to the tail end portion; and an irrigation tube configuredto matably engage the channel with a forward end shaped to dive into thehole and with a rear end extending at least to the tail end portion. Thechannel has a narrowed region shaped to facilitate initiation of a laserwelding process by providing abutting contact between the tubular shelland irrigation tube that, in turn, provides access and point-focusedheating from a laser beam welding operation, thereby facilitatingheating and flowing of the material from the tubular shell into weldedbonding contact with the irrigation tube with minimized physical andaesthetic defects and imperfections, yet without addition of separatewelding material.

In a narrower form, the narrowed region includes deformed material ofthe shell that is deformed and pinched inwardly.

In another aspect of the present invention, a method of manufacturing anophthalmic surgical instrument comprising steps of providing a tubularshell having a tip end portion and a tail end portion, and furtherhaving a channel extending from a hole into the tubular shell near thetip end portion and extending to the tail end portion, providing anirrigation tube shaped to matably engage the channel, and matablyengaging the irrigation tube with the channel with a forward end of thetube positioned in the hole and a rear end of the tube extending to thetail end portion. The method further includes welding the tubular shellto the irrigation tube on both sides of the channel and for a length ofthe channel using material from the tubular shell and irrigation tube,the step of welding specifically not using separately added weldingmaterial, such as welding wire.

In a narrower form of the invention, the channel has a narrowed regionshaped to abutting contact with the irrigation tube when the tube isplaced in the channel, the narrowed region facilitating initiation of alaser welding process by providing access and point-focused heating froma laser beam welding operation, thereby facilitating heating and flowingof the material from the tubular shell into welded bonding contact withthe irrigation tube with minimized physical and aesthetic defects andimperfections, yet without addition of separate welding material.

In still narrower form, the method includes deforming material of theshell to form the narrowed region by pinching and deforming material ofthe shell inwardly at the narrowed region.

In yet a narrower form, the step of pinching and deforming includesforming the narrowed region with two opposing embossments forming abutterfly-like shape with narrower portions near a center of the channeland wider portions on outboard edges of the narrower portions.

In one aspect of the present invention, an article for manufacturing anophthalmic surgical instrument comprises a unitary metal rod blank madeof continuous and contiguous material and that includes a unitary bodyand a tip end portion and a tail end portion. The tip end portion tapersfrom a diameter of the body to a narrowed tip dimension and is designedto support a sonically-vibrating tip extending longitudinally from thetip end portion. The tail end portion tapers from the diameter of thebody to an increased tail dimension. The body and the tail end portionare a solid non-tubular metal rod of titanium material, but the tip endportion is machined to include a multi-diameter-defining internal cavitycomprising a first section defining an end-adjacent first diameter, asecond section defining a second diameter adjacent the first section,and a third section defining a third diameter adjacent the secondsection, with the second diameter being larger than the first and thirddiameters, such that the tip end portion facilitates and supports asonically-vibrating tip. The metal rod blank is constructed to bemachined to form a longitudinal bore through its length and also to bewelded while maintaining a very accurate dimensional shape prior tobeing machined to form the longitudinal bore.

In a narrower aspect, the blank further has a hole in its tip endportion and a channel in an outer surface of at least the body and thetail end portion , the channel extending from the hole to the tail endportion.

In another aspect of the present invention, a method of manufacturing anophthalmic surgical instrument comprises steps of providing a unitarytubular blank made of continuous and contiguous material and thatincludes a unitary body and a tip end portion and a tail end portion,with the body and the tail end portion being a solid non-tubular metalrod of titanium material, forming the tip end portion to form a taperfrom a diameter of the body to a narrowed tip dimension and so that thetip end portion is adapted to operably support a sonically-vibrating tipextending longitudinally from the tip end portion, and forming the tailend portion to form a taper from the diameter of the body to anincreased tail dimension. The method further includes machining the tipend portion to include a multi-diameter-defining internal cavitycomprising a first section defining an end-adjacent first diameter, asecond section defining a second diameter adjacent the first section,and a third section defining a third diameter adjacent the secondsection, with the second diameter being larger than the first and thirddiameters, such that the tip facilitates and supports asonically-vibrating tip end. The non-tubular metal rod is constructed tobe machined to form a longitudinal bore through its length and also bewelded while maintaining a very accurate dimensional shape.

In a narrower form, the method includes machining a longitudinal cavitythrough the rod, the longitudinal cavity including the internal cavity.

In a narrower form, the method includes forming a channel in an outsidesurface of the blank that extends from a hole in the tip end portion tothe tail end portion.

In a narrower form, the method includes steps of providing an irrigationtube shaped to matably engage the channel, matably engaging theirrigation tube with the channel with a forward end of the tubepositioned in the hole and a rear end of the tube extending to the tailend portion, and welding the tubular shell to the irrigation tube onboth sides of the channel and for a length of the channel using materialfrom the tubular shell and irrigation tube.

An object of the present invention is to provide an ophthalmic surgicalinstrument and method of manufacture where the instrument includes atubular shell with channel and mating irrigation tube attached along aside of the shell, but where the tubular shell is initially made from aone-piece continuous and contiguous titanium metal rod machined at a tipend portion to include a multi-diameter cavity for supporting asonically-vibrating tip. A remainder of the rod is not initiallymachined, which eliminates problems of alignment and dimensionaldistortion caused by secondary operations such as welding, but insteadis machined later in the secondary processes, such as after welding. Thepresent innovation eliminates the need to perfectly align and then welda machined tip end to an end of a thin-walled tubular shell, thusavoiding considerable process control and quality issues.

These and other aspects, objects, and features of the present inventionwill be understood and appreciated by those skilled in the art uponstudying the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1-2 are perspective and exploded side views of an ophthalmicsurgical instrument's handset with tubular outer shell and weldedexterior irrigation tube and clocked internal components, embodying thepresent invention.

FIG. 3 is a side view of the tubular shell from FIG. 1, showing a sidewith the tube-receiving exterior channel for receiving the irrigationtube.

FIGS. 4 and 4A are exploded side and exploded perspective views likeFIG. 2 but showing only the internal subassembly of the tip, the horn,the multi-diameter shaft, and the plug.

FIG. 5 is a perspective view showing assembly of the shaft to the hornfrom FIG. 4 using a torque wrench and fixture.

FIGS. 6-7 are perspective and side views showing components from FIG. 5threaded together with a tip to form a first subassembly (i.e. apreassembled tip and horn and shaft) and a plug rotatably supported onthe first subassembly, all positioned in a welding fixture for holdingthe first subassembly (and the tip) in a specific clocked positionrelative to a notch in the plug, the fixture facilitating welding of theplug to the first subassembly in known clocked orientation.

FIG. 8 is a perspective photograph showing a completed welded assemblyof the first subassembly from FIG. 6 (i.e. the tip, horn, shaft, andplug) with the plug welded to the shaft.

FIG. 9 is a partial cross-section taken along line IX-IX in FIG. 3.

FIGS. 10-11 are side views of a rod blank (i.e. rod) of unitary,continuous, and continuous titanium material (i.e. a rod of solidmaterial) that is machined out to form the shell shown in FIGS. 1-3,FIG. 10 being a side view without cross-section, and FIG. 11 being alongitudinal cross-section through the tip end portion to show theinternal multi-diameter machined cavity, the tip being machined prior todrilling out a remaining body to the opposite end of the rod blank.

FIG. 12 is a side view of the shell in FIG. 10 on a channel-side wherethe irrigation tube channel is formed.

FIG. 13 is an enlarged view of the circled area labeled XIII in FIG. 12.

FIG. 14 is a cross section taken along line XIV-XIV in FIG. 13.

FIG. 15 is a perspective view of a welding fixture including weld jawsfor holding the irrigation tube in place on the outer shell when weldingthe irrigation tube to the shell.

FIGS. 16-17 are perspective exploded and perspective assembled views ofa gas chamber for welding the shell and irrigation tube of FIG. 15together; FIG. 16 showing a general shape and position of the gaschamber relative to the jaws in the fixture from FIG. 15.

FIGS. 18-19 are exploded and assembled views of an ophthalmic surgicalinstrument (less electronics and utility wiring/tubing), the outer pieceincluding a shell and weld-attached irrigation tube like that shown inFIG. 2, FIG. 19 also showing the system controls and fluid paths.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As noted above, ophthalmic surgical instruments and systems aregenerally known by persons skilled in the art; therefore, a detaileddescription of their function, use during surgery, electronic internalcomponents, external controls, and general system is not necessary foran understanding of the present invention. Accordingly, the presentdisclosure focuses on the present pre-clocked innovative assembly of aninternal subassembly (with tip, horn, multi-diameter shaft, and plug)mated with an external subassembly (with tubular shell and irrigationtube), including features causing accurate clocking upon assembly,secure mating and defect-free welding interconnection, and includingweld-facilitating features, fixturing and welding processes associatedtherewith.

More specifically, an ophthalmic surgical instrument is provided thatincludes a tubular shell with external channel and mating irrigationtube attached along a side of the shell. Notably, the present tubularshell is made from a one-piece continuous and contiguous titanium metalrod blank machined at its tip end portion to include a multi-diametercavity for supporting a sonically-vibratable tip. A remainder of the rodis not initially machined, which eliminates problems of alignment anddimensional distortion caused by weld-related secondary operations. Thepresent innovation eliminates the need to perfectly align and then welda machined tip to an end of a thin-walled tubular shell, thus avoidingconsiderable process control and quality issues. After the tip endportion is machined and formed (externally and internally), a thru-boreis drilled through a remainder of the rod blank to form the remainingportion of the rod blank into a thin-walled outer shell useful foroperatively holding an internal assembly (i.e. the internal subassemblyincluding the tip, horn, multi-diameter shaft, and plug, describedbelow).

The present apparatus 20 (also called “an ophthalmic surgicalinstrument”) (FIGS. 1-3) includes a first (outer) subassembly includinga tubular shell 21 with channel 22 and mating irrigation tube 23. Thechannel 22 is formed in an outer surface of the shell 21, and extendsfrom an angled radial hole 24 near a tip end 25 of the tubular shell 21to a tail end 26. The irrigation tube 23 fits matably in the channel 22,and includes a bent forward end 27 that fits into the hole 24, andincludes a rear end adapter 28 on the tube 23 extending past an opennotch 40 in the tail end of the channel 22 formed by an annular flange30 of the tubular shell 21. The combination of the tubular shell 21 andirrigation tube 23 form a handle that can be easily and comfortablygrasped by a surgeon, with the surgeon easily recognizing theorientation of the handle by feel due to the clocked (rotationalposition) of the tube 23 and shell 21 to the tip 35.

The present apparatus 20 (FIGS. 2, 4, 4A) includes a second (internal)subassembly including a tip 35, a horn 36, a shaft 37, and a plug 38. Itis noted that various tips are commercially available and can be usedwith the present innovation. The illustrated tip 35 includes an enlargedslightly-curved and/or beveled sharp tip end 35′ on its outer end forcutting (during a surgical procedure), and includes threads on its innerend for threaded secure connection to the tip end portion of the horn36. The horn 36 is designed to sonically vibrate and precisely move thetip end 35′ on the end of the tip 35 for optimal cutting and surgicalapplication. The multi-diameter shaft 37 (also sometimes called a“bolt”) is threaded into a tail end of the horn 36. The plug 38 isrotatably positioned on the shaft 37 and includes an outwardly-extendingannular flange with a notch 40′ along its perimeter. The notch 40′ isdesigned to receive and matingly engage the adapter 28 of the irrigationtube 23 (on the first outer subassembly) when the second internalsubassembly is assembled into the first outer subassembly, as describedbelow. Also, the plug 38 has a notch 40′ that aligns with and generallymatches notch 40′.

FIG. 5 shows threaded assembly of the shaft 37 to the horn 36, andillustrates that the horn 36 is clamped and held by a collet 50 withjaws 51 while the shaft 37 is screwed into the horn 36 and thentightened to the specified torque using a torque wrench 52 and torquewrench adapter 53 (the adapter 53 protecting the hex on the shaft 37).The tip 35 is screwed into the end of the horn 36 with a predeterminedtorsional pretension to prevent accidental release when being vibratedduring use. At this point, the horn 36 and the shaft 37 are interlockedby a strong threaded union. The tip 35 is similarly threaded into a tipend of the horn 36 with a threaded connection, including a significanttorsional pretension as required by the design.

A fixture 45 (FIGS. 6-7) includes a body 46 that holds the second(internal) subassembly in a particular known rotational orientationrelative to the plug 38 while the plug 38 is welded in position on theshaft 37. The fixture 45 includes an adapter-simulating feature 47 (i.e.similar in external shape to the adapter 28 on the irrigation tube 23)that keeps the plug 38 in proper clocked orientation during the weldingprocess by engaging notches 40 and 40′ (FIGS. 3 and 4A). Notably, theillustrated weld can be done without addition of separate weldingmaterial, as described below. Restated, the present innovative processdoes not require the use a welding wire or external welding material.

FIG. 6 shows the first (internal) subassembly (i.e. a threadably-engagedpreassembled tip 35 and horn 36 and shaft 37 from FIG. 5) positioned inthe fixture 45. The plug 38 is slipped onto the shaft 37 and rotatablysupported on the shaft 37 of the first subassembly by the weldorientation fixture 45. The welding fixture 45 includes an end piece 56with a fixture orientation pin (not specifically shown) at location 56′that engages a side edges (or flat side) of the tip end 35′ on the tip35 to orient the first subassembly in a specific clocked (rotational)position. As illustrated, the protruding feature 47 also engages thenotch 40′ in the plug 38, thus orienting the notch 40′ relative to anorientation of the tip end 35′ (i.e. “clocking” the tip 35 to the plug38, such as to a predetermined angular specification such as at 180degrees, such as with +/−5 degrees tolerance, or potentially a tightertolerance such as 2½ degrees). The plug 38 is then welded to the shaft37, fixing its rotational orientation. Notably, as long as replacementtips 35 are purchased from the same supplier, our testing shows that thethreaded end of the common-supplier tips 35 is consistent enough toprovide good and accurate clocking when an original tip 35 is replacedwith a replacement tip 35, such as within +/−5 degrees, or even within+/−2-1/2 degrees. However, the threaded connection between the horn 36and shaft 37 is less consistent, and further there is a taperedinterfacing surface that further renders the connection to have aninconsistent clocked position upon connection. The present innovationsolves that problem.

FIG. 7 illustrates an additional component of the fixture 45, whichincludes a collet/clamp 60 with jaws 61 for gripping the plug 38 and forholding the specific angular clocked position relative to a direction ofthe tip end 35′. It is contemplated that the collet/clamp 60 could alsobe constructed to rotate the plug 38 to a desired orientation. Thefixture 45/60 then holds the plug 38 for initial welding at location 64.

FIG. 8 illustrates the first (internal) subassembly as welded andinterconnected, including the tip 35 fixedly threaded to the horn 36,the horn 36 fixedly threaded to the shaft 37, and the plug 38 fixedlywelded to the shaft 37, all with an angular direction of the tip end 35′and of the notch 40′ being within a angular tolerance such as 180degrees, +/−5 degrees (or a narrower range such as +/−2½ degrees).

The controls for the welding operation may be varied as needed for aparticular welding operation. It is contemplated that the weld can bedone with or without welding wire. In the present innovation, thefollowing parameters were used in welding the illustrated prototype withno weld wire and no added weld material being used. Notably, a skilledartisan will recognize that the laser power and parameters can beadjusted during the welding process for optimal results for a particularapplication:

EXAMPLE: Resonator set-up: Beam expander—2.0, front mirror—150 mm,aperture—5.8 mm to 4.0, rear mirror—150 mm, and rear mirror type flat;Laser Work Parameter Setting: pulseform—N/A, frequency 15 Hz to 40 Hz,pulse duration—4.0 ms to 0.5 ms, volts—241 v to 257 v, energy—3.0 is minto 0.1 is min, E-control—off, beam expander—216, burst number N/A, rampnumber 10, ramp power—N/A, ramp pulse—0.1 ms, gas advance—0.1,delay—0.1, 2-cavities—sim; and Peripherals: nozzle—graphite, nozzlelength—0.600″ to 0.500″, assit gas type—argon, assit gas flow—10 cfh,final focus setting 1.0 mm to 4.0 mm, Z height—1.028″ to 1.150″, andwork coordinate—G54.

As noted above, the present innovation also includes making the entireshell 21 out of a one-piece titanium-metal rod blank. This is done toeliminate several problems. For example, the present innovation avoidsalignment and welding problems associated with welding a machined tiponto the thin-walled extruded tubular shell (e.g. problems includingmechanical alignment, distortion from non-uniform heat of welding andlater cooling, and deformation that occurs in secondary operationsnecessary to attach a machined tip to a front end of a hollow tubularshell). The method of manufacturing the ophthalmic surgical instrument20 comprises steps of providing a unitary one-piece solid rod blank(also called a “rod” herein) (FIGS. 10-14) made of continuous andcontiguous (non-welded) titanium material and that includes a unitarynon-tubular body 51 and a tip end portion 52 (which later becomes tipend portion 25) and a tail end portion 53 (which later becomes tail endportion 26). The tip end portion 53 is machined to define amulti-diameter internal cavity 33, but the body 51 and the tail endportion 53 are temporarily left as a non-tubular solid mass of titaniummaterial. The method includes forming (e.g. machining and/or forming) anouter surface of the tip end portion 52 to form a configured taper froma diameter of the body 51 to a narrowed tip dimension and so that thetip end portion 52 is adapted to operably support a sonically-vibratingbeveled tip 35 with beveled end surface extending longitudinally fromthe tip end portion 52. Also, shape and surface texture of the taper intip end portion 52 and body 51 includes grooves that provide a fingergrip for a surgeon's fingers. The method includes forming the tail endportion 53 to form a flared taper extending from the diameter of thebody 51 to an increased tail dimension. Also, the method includesmachining the tip end portion 52 to include the multi-diameter-defininginternal cavity 33 comprising a first section defining an end-adjacentfirst diameter D1, a second section defining a second diameter D2adjacent the first section, and a third section defining a thirddiameter D3 adjacent the second section, with the second diameter D2being larger than the first and third diameters D1 and D3. The tip endportion 52 is constructed and adapted to clearly receive and support thesonically-vibratable tip 34.

The non-tubular body 51 and tail end portion 53 are believed to be noveland unobvious since they are initially a non-tubular solid mass ofmaterial. By being a solid mass, they can be welded on more easilywithout dimensional distortion. Also, they are constructed to beaccurately machined later in the manufacturing process to form a veryaccurate and centered longitudinal bore (i.e. very accurate thin wallthickness, such as a thickness of less than 1 mm in some places) throughthe length of the shell 21. The solid mass also allows the part to bewelded on while maintaining a very accurate dimensional shape. Notably,after a welding operation, the shell 21 is annealed to improvedimensional stability and accuracy during later secondary processing.

As noted above, the channel 22 is formed in an outer surface of theshell 21, and extends from a hole 24 near a tip end portion 25 and to atail end portion 26 (FIG. 1). The irrigation tube 23 (FIG. 2) ispre-formed to fit matably in the channel 22, with its bent forward end27 (FIG. 1) fitting into the hole 24, and with a rear end adapter 28(FIG. 2) on the tube 23 extending past an open notch 40 of the channel22 formed by an annular flange 30 of the tubular shell 21. The channel22 has an embossed narrowed region 32 (FIGS. 12-14) with protrudingridge 32A. The ridge 32A is configured to abut the tube 23 when firstfixtured together. The embossed area around the narrowed region 32 isshaped somewhat like a butterfly and, when formed, causes the ridge 32Ato slightly rise above the channel 22. As will be recognized by askilled artisan in welding, this ridge 32A facilitates initiation of alaser welding process by providing good abutting contact between thetubular shell 21 and irrigation tube 23 at ridge 32A, both in terms ofproviding access and also providing point-focused heating, such as for alaser beam welding operation. Specifically, it facilitates heating andflowing of the material from the tubular shell 21 into welded bondingcontact with the irrigation tube 23 with minimized physical andaesthetic defects and imperfections, yet without the need for additionof separate welding material. Notably, the embossment feature (i.e.ridge 32A) is consumed and unidentifiable after welding.

The method of manufacturing the ophthalmic surgical instrument 20comprises steps of matably engaging the irrigation tube 21 with thechannel 23 (FIG. 2) with a bent forward end 27 (FIG. 1) of the tube 23positioned in the hole 24 and a rear end adapter 28 (FIG. 2) of the tube23 extending to the tail end portion 26 (FIG. 1). The method furtherincludes laser beam welding the tubular shell 21 to the irrigation tube23 on both sides of the channel 22 with the welding extending a lengthof the channel 22, the weld material being from the tubular shell 21and/or the irrigation tube 23. Notably, the illustrated step of weldingdoes not use separately added welding material, such as welding wire.Notably, even though the present innovation uses zero external weldmaterial and laser welding, it is contemplated that a scope of thepresent innovation includes supplying added welding material and/orusing a different welding process.

Notably, the irrigation tube must be fully “sealed” after welding. Inother words, when fluid in the irrigation tube fills up the noseconeportion of the shell, no fluid can leak back to the outside of the handpiece. The illustrated “butterfly wing” design is believed to greatlyassist in creating a tight and good seal during the welding process.This is believed to be in part because the thinning at a specific pointallows the manufacturer to use the laser and fixturing to “pinch” thematerial together, resulting in an improved and better and moreconsistent seal.

Welding titanium material is difficult, and requires that the area to bewelded be oxygen-free during the welding operation. The fixture 50 (FIG.15) and gas chamber 51 (FIGS. 16-17) are designed to facilitate thepresent welding operation, including making the operation more efficientwhile using less wasted oxygen-eliminating gas during the weldingoperation. The fixture 50 (FIG. 15) includes multiple L-shaped weld jaws52-54 (three being illustrated). One jaw 52 is designed to abut the tube23 and hold the irrigation tube 23 in the channel 22 (FIG. 9) andagainst the shell 21. The other two jaws 53-54 are radially spaced tooppose the jaw 52 and securely hold the assembly (including the shell21) during the welding process. The L-shaped jaws 52-54 each include ashell-engaging longitudinally-protruding arm 55 for engaging the shell21/tube 23, and include a radially-extending base-supported arm 56adjustably supported to move the shell-engaging arm 55 into and out offixturing clamped engagement with the shell 21 and tube 23.

The gas chamber 51 (FIG. 16) includes a main body 61, an aperture endcap 62 (for receiving the shell-engaging arms 55 of the jaws 52-54), aclosed end cap 63, and a cover slide 64. The main body 61 includes anopen side covered by the cover slide 64, and the cover slide 64 isslidably mounted in track grooves 65 along the open side of the mainbody 61. A window 66 in the cover slide 64 provides access for a laserbeam for the welding operation.

The controls for the welding operation may be varied as needed for aparticular welding operation. For example, the following steps andparameters were used in welding the present prototype, such as isillustrated in FIG. 1.

Three titanium subcomponents (FIGS. 15-17) are initially assembled andthen welded, the subcomponents including: 1) the one-piece shell outer21, 2) the irrigation tube 23, 3) the rear end adapter 28 (also called“female luer adapter”) fitting on end of irrigation tube 23. Notably,the adapter 28 can be welded to the tube 23 ahead of welding the tube 23to the shell outer 21 if desired. The welding creates a continuousleak-proof joint entirely around and along the tube 23 and shell 21 thatis aesthetically appealing, and that is structurally robust to withstandthe rigors of many cycles of surgery, cleaning, and rough handling.Notably, the illustrated welding process did not utilize a weld wirefiller to overcome poor fit-up or joint design.

The illustrated welding process is somewhat complex and has manyinterrelated components to facilitate a high-quality,excellent-appearance weld. However, generally stated:

-   -   a. The actual weld parameters are controlled within the part run        program. The program has several parameter changes to address        specific challenges in target areas on the part. The “recipes”        within the program include changes in Feed rates, Pulse        Frequency (Hz), Energy (Joules), Pulse Duration (ms), and Energy        Ramping (upslope/downslope). The energy levels vary from 2.5 Js        for the “Butterfly seal” to 0.95 is in the delicate nosecone        area. A person of ordinary skill in welding of titanium and in        laser welding would know how to optimize those parameters, such        that a detailed discussion of the parameters is not required in        this disclosure.    -   b. Presenting the assembled part for weld is done utilizing a        high performance, high precision three-jaw chuck with specially        designed jaws (FIG. 15) and gas chamber (FIGS. 16-17) that allow        a proper angle of presentation of the laser beam to the part for        a completed one operation weld. This jaw-fixture and gas chamber        allows for angle of approach to exceed 65 degrees.    -   c. Removing oxygen from the welding environment is critical for        successful titanium welding, because Oxygen absorbed into the        weld creates structural defects, reduces strength, and creates        visual imperfections. The illustrated “Gas Chamber” (see FIGS.        16-17) enhances the introduction of shielding gas to the weld        zone while purging the oxygen from the work envelope surrounding        the part, yet does so in a manner minimizing the amount of        purging gas required. The illustrated arrangement of FIGS. 16-17        is sometimes referred to as a “glove box” welding system, and is        part-specific and is generally designed to reduce the costs of        wasted gas while improving processing throughput.    -   d. Post processing of weld is an important component of the        processing. While heat treating of titanium is generally known,        we have incorporated a stress relieving process with good        temperature/time control in order to maintain the tolerances        required for subsequent processing and ultimately the finished        product. The present process is believed to be new and        unobvious, since it is not presently specified in known        processes for forming parts similar to the present tubular        shells 21, yet it yields a superior finished product, which is        contrary to conventional thinking when using welding,        particularly when welding without adding additional welding        material such as from a welding wire.

To assemble the apparatus 20 (FIG. 15), FIG. 18 illustrates the internalsubassembly (i.e. the tip 35, horn 36, shaft 37, and plug 38 andincluding electrical wires operably connected to the horn 36) arepositioned inside the external subassembly (i.e. the fully-formed outershell 21 with irrigation tube 23 and adapter 28), and then friction-fitthe tail end cap 39A (FIG. 18) on a tail end of the outer shell 21 (withthe wires extending through the wiring port in the end cap 39A), thusholding the assembly together. Thereafter, as shown in FIG. 19, theadapter 28 is connected to the irrigation source/path (i.e. fluid goinginto the eye to equalize pressure), the tail of the interior subassembly(i.e. the tail of the multi-diameter shaft 37, which protrudes throughthe end cap 39A) is connected to the aspiration/fluid-debris-removalpath (i.e. fluid leaving the eye that is sucked out along with organicmaterial such as a lens and cataract), and electronic/sonic/handsetwiring/tubing controls are connected the equipment system control(electronics and utilities) (or otherwise connected as required by theequipment system manufacturer).

It is to be understood that variations and modifications can be made onthe aforementioned structure without departing from the concepts of thepresent invention, and further it is to be understood that such conceptsare intended to be covered by the following claims unless these claimsby their language expressly state otherwise.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A subassembly for anophthalmic surgical instrument comprising: a multi-diameter shaft; ahorn fixedly threaded into the shaft and that is constructed to providesonic vibration energy to an end opposite the shaft; a surgical tip forophthalmic surgery including a tip end at one end and a threaded endthreadably engaging the horn opposite the shaft, the tip end defining aface direction; and a plug on the shaft and having a flange with anangle-locating feature; and weld material holding the plug on the shaftin a selected angular and longitudinal position with the angle-locatingfeature having a predetermined angular clocked relation to the facedirection of the tip end.
 2. The subassembly of claim 1, wherein theangle-locating feature is a recess in an annular flange on the plug. 3.An ophthalmic surgical instrument comprising an outer subassemblyincluding a tubular shell and an irrigation tube attached to a side ofthe shell, and including the internal subassembly of claim 2 assembledinto the outer subassembly with the recess engaging the irrigation tubeon the annular flange of the plug, thus causing the tip end to be in adesired angular clocked position relative to the irrigation tube on theshell.
 4. A method of manufacturing an ophthalmic surgical instrumentcomprising: providing a multi-diameter shaft; providing a horn adaptedto generate sonic vibration energy; fixedly threading the horn and theshaft together; providing a surgical tip for ophthalmic surgeryincluding a tip end at one end and a threaded end; threadably engagingthe tip into the horn opposite the shaft, the tip end defining a facedirection; providing a plug on the shaft and having a flange with anangle-locating feature; and welding the plug to the shaft in a selectedangular and longitudinal position with the angle-locating feature havinga predetermined angular clocked relation to the face direction of thetip end to create an internal subassembly.
 5. The method of claim 4,wherein the angle-locating feature is a recess in an annular flange onthe plug, and wherein the step of welding the plug includes engaging therecess with a feature in a welding holding fixture.
 6. The method ofclaim 5, including providing an outer subassembly having a tubular shelland an irrigation tube attached to a side of the shell, and includingassembling the internal subassembly into the outer subassembly with therecess engaging the irrigation tube on the annular flange of the plug,thus causing the tip end to be in a desired angular clocked positionrelative to the irrigation tube on the shell.
 7. An article for use inmanufacturing an ophthalmic surgical instrument comprising: a unitarymetal rod blank made of continuous and contiguous material and thatincludes a unitary body and a tip end portion and a tail end portion;the tip end portion having an outer surface tapering from a diameter ofthe body to a narrowed tip dimension and being designed to operablysupport a sonically-vibrating tip extending longitudinally from the tipend portion, and the tail end portion having an outer surface taperingfrom the diameter of the body to an increased tail dimension; the bodyand the tail end portion being an unwelded solid non-tubular metal rodof titanium material, but the tip end portion being machined to includea multi-diameter-defining internal cavity comprising a first sectiondefining an end-adjacent first diameter, a second section defining asecond diameter adjacent the first section, and a third section defininga third diameter adjacent the second section, with the second diameterbeing larger than the first and third diameters, the metal rod blankbeing constructed to be machined to form a longitudinal bore through itslength and also to be welded on while maintaining a very accuratedimensional shape prior to being machined to form the longitudinal bore.8. The article defined in claim 7, wherein the blank further has a holein the tip end portion and also a channel in an outer surface of atleast the body and the tail end portion extending from the hole to thetail end.
 9. A method of manufacturing an ophthalmic surgical instrumentcomprising steps of: providing a unitary tubular blank made ofcontinuous and contiguous material and that includes a unitary body anda tip end portion and a tail end portion, with the body and the tail endportion being a solid non-tubular metal rod of titanium material,forming the tip end portion to form a first taper from a diameter of thebody to a narrowed tip dimension and so that the tip end portion isadapted to operably support a sonically-vibrating tip extendinglongitudinally from the tip end portion; forming the tail end to form asecond taper from the diameter of the body to an increased taildimension; and machining the tip end portion to include amulti-diameter-defining internal cavity comprising a first sectiondefining an end-adjacent first diameter, a second section defining asecond diameter adjacent the first section, and a third section defininga third diameter adjacent the second section, with the second diameterbeing larger than the first and third diameters, such that the tip endportion is adapted to support the sonically-vibrating tip, thenon-tubular metal rod being constructed to be machined to form alongitudinal bore through its length and also be welded whilemaintaining a very accurate dimensional shape.
 10. The method defined inclaim 9, including machining a longitudinal cavity through the rod, thelongitudinal cavity including the internal cavity.
 11. The methoddefined in claim 9, including forming a channel in an outside surface ofthe blank that extends from a hole in the tip end portion to the tailend portion.
 12. The method defined in claim 11, including steps ofproviding an irrigation tube shaped to matably engage the channel,matably engaging the irrigation tube with the channel with a forward endof the tube positioned in the hole and a rear end of the tube extendingto the tail end portion, and welding the tubular shell to the irrigationtube on both sides of the channel and for a length of the channel usingmaterial from the tubular shell and irrigation tube.
 13. An ophthalmicsurgical instrument comprising a combination including: a tubular shellhaving a tip end portion and a tail end portion, and further having achannel extending from a hole into the tubular shell near the tip endportion and extending to the tail end portion; and an irrigation tubeconfigured to matably engage the channel with a forward end shaped todive into the hole and with a rear end extending at least to the tailend portion; the channel having a narrowed region shaped to facilitateinitiation of a laser welding process by providing abutting contactbetween the tubular shell and irrigation tube that in turn providesaccess and point-focused heating from a laser beam welding operation,thereby facilitating heating and flowing of the material from thetubular shell into welded bonding contact with the irrigation tube withminimized physical and aesthetic defects and imperfections, yet withoutaddition of separate welding material.
 14. The instrument of claim 13,wherein the narrowed region includes deformed material of the shell thatis deformed and pinched inwardly.